Problems after installation

hi all, hope u guys here can help me out. i have just done a crvtec andnow after i just installed,it givin problems. the setup is stock but i am running very very richand the engine check light is on! durin idle its fine for awhile than it will shoot to 1500rpm. wat should i do? i am usin a b16 head and a b20b block. pls help